iPhone charger teardown shows astounding miniaturization.

There’s no question that Apple has their industrial design down pat; comparing a cell phone charger made by Blackberry or Motorola to the tiny 1-inch-cube Apple charger just underscores this fact. [Ken Shirriff] posted a great teardown of the Apple iPhone charger that goes through the hardware that makes this charger so impressive.

Like most cell phone chargers and power supplies these days, Apple’s charger is a switching power supply giving it a much better efficiency than a simple ‘transformer, rectifier, regulator’ linear power supply. Inside the charger, mains power is converted to DC, chopped up by a control IC, fed into a flyback transformer and converted into AC, and finally changed back into DC, and finally filtered and sent out through a USB port.

The quality of the charger is apparent; there’s really no way this small 1-inch cube could be made any smaller. In fact, if it weren’t for the microscopic 0402 SMD components, it’s doubtful this charger could be made at all.

Comparing the $30 iPhone charger of a cheap (and fake) iPhone charger, the budget charger still uses a flyback transformer but there are serious compromises of the safety and quality. The fake charger doesn’t use a power supply controller IC and replaces the four bridge diodes for a single diode to rectify the AC; a very efficient cost-cutting measure, but it does lead to a noisier power supply.

There’s also the issue of safety; on the Apple charger, there is a (relatively) huge physical separation of ~340 VDC and your phone. With the off-brand charger, these circuits are separated by less than a millimeter – not very safe, and certainly wouldn’t be UL approved.

EDIT: In case a 1-inch cube wasn’t impressive enough, check out the euro version of the iPhone/iPad charger. It supplies 1A @ 5V, and isn’t much thicker than the USB port itself. Thanks [Andreas] for bringing this to our attention. If anyone wants to do a teardown of the euro version, send it in on the tip line.

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I’d like to point out that these are usually not a chargers as such but transformers or “power supplies”. The charging circuitry is almost always inside the phones these days and the transformers only supply steady 5 volts to the phone.

Kindle chargers are also the little tiny one inch cube (with a flared neck sticking out for style points). And yes, modern Blackberry chargers are the same size as well. Making a 1 inch cube that puts out power on USB is not hard anymore.

Apple’s aesthetics are as pleasing as a toilet. All those rounded corners. Hello Kitty, they started this rounding off in the 70’s. For little children not adults. The need for separation of line and low voltage in the charger is necessary but a cube is the worst shape to stuff this into, so aesthetics trumps safety still. 340v needs translated to length please, for comparison.
Some unrated cell phone chargers are blatant transmitter-jammers! We need a federal firewall to keep this crap in China.

Design wise it’s simple, clean, and matches all the other stuff they make. It looks good and works, that’s all it needs to do. They fit all that good stuff in a plug that doesn’t fall out of the wall and doesn’t block another outlet. What could be better? You already said round is for little children, so how would you, as an adult, design this product?

But there is a Federal fire wall, we call it the FCC ;) This past week I had to get a new mobile phone, of course all the extra chargers that I have for the old phone don’t have the correct phone end connector. While I was in “the city” I went to wall mart to pick up a car charger. I picked up a rayovac branded package that had both the car and AC units, but I failed to note the packages lacked the logos indicating FCC “type acceptance” or UL “approval”, quotes used because those term no longer mean what they meant or never meant what people thought they meant. Until enough people experience interference, understand why they are experiencing that interference, and it’s something they should take up with the FCC, the firewall will never work. The investor class see FCC regulations as interference of a different sort, and are likely to block even FCC action against know interfering devices, much less support type acceptance enforcement as the preemptive measure it’s supposed to be.
In regards to visual aesthetics, why should they matter if a product performs it’s function well, as in case of the Apple product? Cube shaped power supplies have existed since the inception of the wall receptacle mounted power supplies. Don’t dismiss rounded corners as kid friendly only, they are friendlily to an aging adult populations whose skin will bleed more easily as they get older. US cars started to get rounded softer edges surfaces in the mid-late ’60s my guess that influenced the same for everything else in our car centric society.

Does anyone know why the secondary ground is connected to DC-hi via Y1 as opposed to the primary ground? Is this the lowest impedance path? I realize Y1 is there to provide a path for currents that would otherwise cause EMI. My question is motivated by this article:

What I find incredible is that they still use rice and mustard in modern electronics, and that they’re superstitious enough to include a lucky penny inside the case to guard against fire even though it nearly doubles the size of the device!

Awesome, very thoro write-up. Wish I had the patience to do that much research, particularly with that patented active clamping circuit. Just got me wondering where else the same idea could be usefully applied, were it not patented of course.

You know the rules. If everyone else uses 0402 components that’s just standard stuff. If Apple use some it’s innovative design genius and changes the world. An Apple patent on 0402 (and the numbers 0, 4 and 2 in any order) is probably being processed right now.

Ok. 0402s are small when soldering them by hand but lets not kid ourselves. Pick and place could do smaller. They could squish this with 0201s or 01005s but in a power setting it likely wouldnt have enough wattage to be really useful. It really looks like the caps and through hole pieces are the limiting factor.

I like legit can’t wait for someone to tear down the european version! It’s considerably smaller than the US one, and forces all of the Apple critics to jump out the window to save themselves from humiliation!

Doesnt matter how nice it is if theyre using those built-to-explode SAMXON caps. Also, whats with the boner the entire internet has for this PSU? This article is all over the nets! Relax people, its just a small power supply built with off-the-shelf parts on a small board. Whoop-dee-effin-do.

Sorry to be ranty, I’m just confused about why this is getting more attention than far more interesting/elegant builds.